title: The origin and role of erythema after carbon dioxide laser resurfacing. A clinical and histological study.
abstract: BACKGROUND
  Transient erythema, which can last up to 3 months after carbon dioxide (CO2) laser skin resurfacing, is a usual side effect with pulsed or rapidly scanned CO2 lasers.
  
  
  OBJECTIVE
  We evaluated the cause of erythema in the clinical setting and by histology in order to determine if and how we may decrease it, or even eliminate it.
  
  
  METHODS
  Ten patients who underwent resurfacing were recruited to this study. Skin punch biopsies were taken at 0, 7, 21, and 90 days and analyzed by light microscopy.
  
  
  RESULTS
  Erythema was noticed from about day 8, when the crusting on the skin surface was exfoliated. It reached its maximum intensity after 14 days, and had disappeared by 60-90 days. Histology showed an early inflammatory response, with an immature neopithelium, and rich vascularization. The normal epidermis had returned by 90 days, and during this period there was reduced optical scattering and absorption in melanin.
  
  
  CONCLUSIONS
  Although the erythema is an unwanted side effect in the patient's eyes, it is to be expected and thus represents the effects of a combination of epidermal immaturity, reduced melanin absorption of light, reduced dermal optical scattering, and increased blood flow secondary to the surgically induced inflammatory response.
authors.affiliation: Instituto Médico Vilafortuny, Cambrils, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Trelles
authors.forename: S
authors.initials: S
authors.lastname: Mordon
authors.forename: L O
authors.initials: LO
authors.lastname: Svaasand
authors.forename: T K
authors.initials: TK
authors.lastname: Mellor
authors.forename: J
authors.initials: J
authors.lastname: Rigau
authors.forename: L
authors.initials: L
authors.lastname: Garcia
mesh_terms: D000368:Aged; D001707:Biopsy, Needle; D062109:Dermatologic Surgical Procedures; D004890:Erythema / Q000209:etiology / Q000473:pathology*; D005145:Face / Q000601:surgery*; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects*; D008875:Middle Aged; D015361:Rhytidoplasty / Q000379:methods; D012867:Skin / Q000473:pathology; D015595:Skin Aging